The present invention relates to the field of collision energy absorption systems, and more particularly, to a lightweight, extremely effective energy absorption system for improving the energy management effectiveness of the primary crush zone of a vehicle. The invention has particular utility as a collision energy absorption system for impact of vehicles, and will be described in connection with such utility, although other utilities are contemplated.
While protecting a vehicle's occupants from injury in a crash is a challenge for every vehicle manufacturer, in the case of a small, lightweight car, it is a particular challenge, due in part to the limited ability of small cars to absorb collision energy, and the relative short crush distance which is a major factor in providing a ride-down or deceleration distance for the vehicle occupants. In a conventional steel-bodied vehicle, the body panels are shaped and reinforced to form crush or crumple zones that are designed to absorb collision energy while protecting the passenger compartment or so-called occupant interior cage. Smaller, lighter weight cars offer particular challenges to engineers to provide adequate crash energy absorption. Efforts to improve passenger compartment protection typically add weight to the vehicle and thus adversely affect fuel economy. Moreover, simply reinforcing passenger compartment structural integrity may impose intolerably high "G" loads on occupants, as a result of strengthening the vehicle without also improving deceleration properties of the vehicle.
In addition to passenger protection, there are other considerations. For example, energy conservation requires reducing weight. The most dramatic method of reducing weight in mass produced conventional vehicles is to downsize the vehicles. However, crash data and tests on smaller vehicles show that small vehicles generally provide less protection to passengers, especially in collisions with larger vehicles.
Composite materials can provide significant weight savings when used to make vehicle components. Although composite materials have been produced for many years and have found their way into many non-structural components of vehicles, composite materials heretofore have not been used in critical crash protection areas, in part because composite materials typically are more brittle than steel, tending to break rather than bend, buckle or crumple and absorb energy.